Subband Group Bandwidth Difference Encoding for Audio Signal Configuration
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Solution Overview
Problem
Existing audio coding methods require a large number of bits to define subband configurations, which is inefficient for transmitting or storing subband configuration data, especially when subbands have different bandwidths adapted to psycho-acoustic properties of human hearing.
Innovation Solution
The method treats the first, penultimate, and last subband groups differently from the others, using subband group bandwidth difference values for encoding, and employs a coding scheme that uses a fixed number of bits for certain values, such as unary coding for small bandwidth differences and fixed coding for larger differences, reducing the overall number of bits required for transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If traditional subband configuration encoding is used, then complete subband configuration information is transmitted, but the number of bits required is large (23 bits)
Solution Approach 1:
The patent applies different encoding strategies to different subband groups based on their characteristics. The first subband group uses one encoding approach, while subsequent subband groups use bandwidth difference values relative to the previous group. This local differentiation reduces the overall bit requirement while preserving necessary configuration information.
Solution Approach 2:
Instead of transmitting absolute bandwidth values for each subband group, the patent changes the parameter representation to transmit bandwidth differences relative to the previous group. This parameter transformation significantly reduces the number of bits needed, especially when bandwidth changes are small between adjacent groups.
2Productivity
If subband groups are combined to adapt to psycho-acoustic properties, then audio coding efficiency is improved, but the complexity of defining and transmitting configuration data increases
Solution Approach 1:
The patent segments the subband configuration into groups where adjacent subbands with similar characteristics are combined. This segmentation allows the use of differential encoding within groups, reducing the complexity of configuration data transmission while maintaining the benefits of psycho-acoustically adapted subband structures.
Data Source
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AI summary
For an efficient encoding of subband configuration data the first, penultimate and last subband groups are treated differently than the other subband groups. Further, subband group bandwidth difference values are used in the encoding. The number of subband groups N SB is coded using a fixed number of bits representing N SB — 1. The bandwidth value B SB [1] of the first subband group is coded using a unary code representing B SB [1] — 1. No bandwidth value B SB [g] is coded for the last subband g = N SB . For subband groups g = 2,...,N SB — 2 bandwidth difference values ΔB SB [g] = B SB [g] — B SB [g — 1] are coded using a unary code, and the bandwidth difference value ΔB SB [N SB — 1] for subband group g = N SB — 1 is coded using a fixed number of bits.